Well, usually the RC is up for everybody (to test) a few weeks after Ubuntu's release. Usually a few weeks after that the final release is made. Best way to keep track of what is happening is to follow the blog: http://blog.linuxmint.com/ as Clem shares important news there The ISO images are tested ahead of public release by Linux Mint's testing team. They have a defined set of test-cases to run through before the public release of the RC is approved, and you can follow progress of that on the Community website: http://community.linuxmint.com/iso